Mobo only powers up without the 4pin cpu power plugged in

It's always a bad sign when someone mentions a PSU without giving a brand or model.

With the 4-pin plugged in, will the board briefly power up when you unplug the PSU, leave it for a minute, then plug it back in?

Did you install the motherboard standoffs only in those places that correspond to screw holes in the motherboard?

Have you tried with just one stick of RAM installed? What are the specifics of your RAM?

Have you inspected the CPU for bent pins, and foreign material?

Have you tried re-seating everything??

I tend to look at what you have done... You went inside the case, tinkered, and poof it stopped working. There is a good chance that a cable or card was bumped. If I were you, I would unplug EVERYTHING, pull the motherboard out, and put it back together as you originally had it (without the temp gauge), put NEW thermal compound on the CPU heat sink, while the CPU is out examine the pins carefully.

In fact I would do this exactly, once everything has been unplugged/removed and the motherboard put back in, only plug in the bare minimum for the system to boot up.

Video card (make sure the PCI-E power is supplied to the card, if your card needs it).
1 stick of memory in SLOT 1
CPU 12v power
24pin Motherboard Power
CPU heat sink (Of course!)

If it refuses to make it to the POST screen, try a different Video Card (if you have one). You didn't mention that you were using a video card though, but If you are using a video card, remove it and use the on-board video.

If the system wont boot now try a different stick of memory in SLOT 1.
No boot yet? - Try the same stick in different slots, try them all. If it still wont boot try the other stick in the same manner (different slots). If you have any extra memory anywhere else, give it a try in the same way.

If the system still will not boot after all this, try a different CPU (if you have one). Try the CPU in a different motherboard (if you have one). You mentioned that a different power supply has the same effect, so I doubt that's the problem.

If you don't have extra parts to try I would say it's either the memory, motherboard, or CPU. Hard to say what it is.

If you manage to get it to boot during the process you will be able to find the problem pretty easily. Plug in one component at a time, hard drive try to boot again; if it refuses to boot the hard drive is the problem... etc etc so on and so forth.

Btw - Did you overclock anything at anytime? If so, read your motherboard manual and reset the BIOS. In fact just go ahead and reset the BIOS, it might fix your problem (stranger things have happened).

"G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory"

Again, please be more specific. Newegg has about 8 different kits matching this description:
http://www.newegg.com/Product/Prod [...] C2%206400)

Some of those might be problematic with your board.

Your system is not booting up. What is happening is that your power comes on with just the 24-pin connected, but the board never actually posts. When you actually connect the CPU power, the board tries to post, fails, and turns itself off.

Memory is always the first suspect in such cases. If you are using a highly volted kit, such as the 2.1V, that might not boot up without a BIOS adjustment first.


"Yes, only screws in the correspond holes on the board."

Not the screws, the standoffs is what I'm interested in. The ONLY place the back of the board should make contact is on the standoffs, and only in the proper places.

I would not have recommended the Neopower. Not a particularly good line from Antec. The Trio, Earthwatts, TPQ, or Signature lines are better. I doubt that's the issue though.

"I taped the sensor to the heat sink of the CPU. Thats when it started not booting up right."
That won't give you a meaningful temp reading anyway. I would certainly unplug the LCD and remove the sensors.

In fact, you should build minimally out of the case at this point, if nothing else has worked... on a cardboard box is good, but not on an anti-static bag as those can actually conduct.

ir_efrem gave you a bunch of good advice.

If your M/b is 775, check to make sure there is no dirt or fluff caught in the cpu pins.